LOANS RECEIVABLE: Loans receivable, excluding loans held for sale (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 811,376	$ 779,432
Less: Allowance for loan losses		10,766	10,528	$ 9,885	$ 10,762
Loans receivable, net		800,610	768,904
Commercial and construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		706,270	660,189
Commercial and construction | Commercial business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		137,672	107,371
Less: Allowance for loan losses		1,668	1,418	1,048	1,263
Commercial and construction | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		450,597	447,071
Less: Allowance for loan losses		4,914	5,084	4,273	4,268
Commercial and construction | Land
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		15,337	15,875
Less: Allowance for loan losses		220	228	325	539
Commercial and construction | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		63,080	43,715
Less: Allowance for loan losses		822	297	712	348
Commercial and construction | Real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		39,584	46,157
Less: Allowance for loan losses		618	714	416	769
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		105,106	119,243
Less: Allowance for loan losses		1,809	2,099	$ 2,403	$ 2,548
Consumer | Real estate one-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		90,109	92,865
Consumer | Other installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[1]	$ 14,997	$ 26,378

[1] Consists primarily of purchased automobile loans totaling $12.9 million and $23.6 million at March 31, 2018 and 2017, respectively.